Desmid of the month
December 2014

Staurastrum echinatum

St. echinatum is a spiny desmid that may be confused with a number of other Staurastrum species. Characteristic features are the widely open sinus and the closely set, rather short, thorn-like spines. Often, part of the spines are furcate and usually the downwardly projected spine at the basal semicell angles is larger than those elsewhere on the semicell surface. Zygospores are irregularly globose and furnished with short, stout spines which are two- or threefold furcate. St. echinatum is characteristic of acidic, oligotrophic (but slightly minerotrophic) bog pools. In the Dutch province of Drenthe it is of occasional occurrence, elsewhere in the Netherlands it is very rare. Zygospores were only very recently described for the first time (Van Westen & Coesel 2014).